This commit removes the statically created XnioWorker which is an
"active" component and should not be created automatically and could
lead to resource leaks. Instead XnioWorker is now required at
construction aligning better with WebSocketClient#connectionBuilder
which also does not have a "default" worker option.
Since the XnioWorker is the main input for creating a ConnectionBuilder
we now create the ConnectionBuider in a protected method and then allow
a Consumer<ConnectionBuilder> to configure it further as opposed to the
Function<URI, ConnectionBuilder> used previously.
This commit also removes default SSL context initialization for RxNetty
to better align with other client implementations.
Issue: SPR-14527
e4d39bb86f